NASHUA — Matthew Packer pleaded guilty on Friday to second-degree murder in the stabbing death of a local EMT and is expected to serve at least 30 years in prison.

Packer, 21, formerly of Nashua, showed no emotion at his court hearing, staring straight ahead and answering simple questions from the judge while the victim's friends and family wept.

According to Assistant Attorney General Peter Hinckley, Packer has shown no remorse for the Oct. 9, 2011, attack that resulted in 16 stab wounds to Paul Frontiero III, 27, including one fatal puncture wound to the heart.

Under a negotiated plea agreement, Packer will avoid a trial. He pleaded guilty to second-degree murder and two counts of first-degree assault against Jill Arnold and Kathryn Libby — two women Frontiero protected during the attack.

The state is recommending a sentence of 60 years to life in prison, while the defense is proposing a sentence of 30 years to life.

Hillsborough County Superior Court Judge Diane Nicolosi will determine the sentence, and a sentencing hearing has been scheduled for Aug. 21, at which time several of Frontiero's family members are expected to speak.

Arnold and Libby, who were injured when Packer took out a folding knife on Spruce Street and assaulted them, were in court on Friday for the hearing. The young women, both 29, cried while Hinckley described the attack to the judge.

Hinckley shared details he learned from Packer's former cellmate, who told investigators that Packer had no remorse for his actions. Instead, Packer told his cellmate that he "enjoyed the sensation" of the knife breaking into Frontiero's skin, describing in detail how it felt when the knife hit Libby's teeth when he slashed her face, according to Hinckley's testimony.

Cathy and Paul Frontiero Jr., the victim's parents, stood side by side outside of the courtroom following Packer's plea, maintaining their son was a good man who had a lot of great opportunities in his future.

"He has left a hole in our hearts and a void in our lives," Cathy Frontiero said of Packer, describing him as a troubled young man. She added that the family is relieved that Packer will be behind bars for a significant period of time.

"It has been a nightmare that we are living all over again," said Cathy Frontiero, responding to Friday's testimony. " ... to hear it again, it is just heartbreaking."

Hinckley said the plea bargain was a difficult decision for the Frontiero family and the two remaining victims, but they ultimately consented.

"I understand you have been treated for a mental health issue in the past," Nicolosi said to Packer, who acknowledged he was previously treated and prescribed medications for post traumatic stress disorder.

Previously, Packer's defense team filed a notice of defense claiming Packer was legally insane during the stabbing, and had planned on introducing evidence at trial that Packer was suffering PTSD at the time of the attack, according to court documents.

Julia Nye, Packer's public defender, said a medical expert will likely address the PTSD issue during Packer's sentencing hearing.

Because of his brave and selfless actions that night, Frontiero was previously presented with a posthumous New Hampshire Union Leader Hero Award for intervening to save the lives of Libby and Arnold.

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